The present invention relates to a device for manual actuation of a gas distribution valve connected to a burner.
It is well known that gas burners, for instance connected to boilers of a heating system or hot water production, are controlled by gas distribution valves provided with safety devices so that gas delivery is effected only in presence of a flame. For this reason at starting when the flame begins to be produced, gas delivery is ensured by a manual actuation of the valve held in an unstable position and only the direct, manual and voluntary action of the operator allows discharge of gas. A thermocouple sensing the presence of the flame thus reaching a predetermined temperature, allows to pass from the position of valve opening instability to the stable position and subsequently to low, medium and high gas erogation phases. In boilers such as wall boilers for producing hot water or for heating systems, the manual actuation of the gas distribution valve connected to the burner, is easily effected as the boiler is installed in an easily reachable and comfortable position.
On the contrary actuation of similar devices not used for boilers but for instance for fireplaces as shown in FIG. 1, is not at all easy, where the burner 41 has the gas distribution valve 42 generally close to the burner 41 so that the manual actuation of the valve 42 according to the presently used technique would be really problematic as it is very inconvenient and dangerous.
Some manufacturers approached the problem of remote control of the distribution valve through a set of leverages acting on the stem controlling the various positions of gas distribution. Such leverages resulted to be rather unsuitable for effecting a safe piloting action of the gas distribution valve especially in the starting phase when the valve has an unstable position. This happens because the frictions inevitably produced at the joints of the leverages after several hours of operation, may block the valve at positions that should be unstable thus preventing a correct operation of the safety devices.
The object of the present invention is to overcome the limits of the prior art. Indeed the main object is to carry out a device for manual actuation of gas distribution valves that is reliable and is not sensitive to aging and deterioration conditions due to use.
Another object is to provide a remote actuation device which is simple, cheap and of easy use and easily applicable to presently available distribution valves as well.
Another object is also to provide a device which is cheap and easily applicable to the users in need thereof.
These and other objects that will be better apparent from the following description are attained by an actuation device for a gas distribution valve connected to a burner provided with a thermocouple controlling the presence of flame, said valve comprising: a gas inlet duct; two or more gas delivery ducts; gas interception means controlling selectively said inlet duct and said delivery ducts that can be actuated through the axial movement of a stem of said valve; electrical means cooperating with said thermocouple and said interception means of the gas inlet duct, where said device is characterized by comprising a flexible metal wire sliding inside a sheath fixed at one end to said stem and at the other end to a control lever rotatable relative to a support plain according to discreet positions corresponding to the various positions of the interception means.
Advantageously according to the invention the flexible metal wire protected by sheath, ensures transmission of motion from the lever to the control stem without significant friction. It is therefore clear that such a device is particularly adapted to be used near heat sources such as a gas burner.